21311320201 has 4 divisors (see below), whose sum is σ = 21447061252. Its totient is φ = 21175579152.

The previous prime is 21311320181. The next prime is 21311320229. The reversal of 21311320201 is 10202311312.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 4218372601 + 17092947600 = 64949^2 + 130740^2 .

It is a cyclic number.

It is not a de Polignac number, because 21311320201 - 2¹¹ = 21311318153 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21311320501) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 67870290 + ... + 67870603.

It is an arithmetic number, because the mean of its divisors is an integer number (5361765313).

Almost surely, 2^21311320201 is an apocalyptic number.

It is an amenable number.

21311320201 is a deficient number, since it is larger than the sum of its proper divisors (135741051).

21311320201 is a wasteful number, since it uses less digits than its factorization.

21311320201 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 135741050.

The product of its (nonzero) digits is 72, while the sum is 16.

Adding to 21311320201 its reverse (10202311312), we get a palindrome (31513631513).

The spelling of 21311320201 in words is "twenty-one billion, three hundred eleven million, three hundred twenty thousand, two hundred one".